Influence of OH -/SiO 2 ratio (alkalinity) on the particle size distribution and structure of the β zeolite synthesized during a shorter crystallization period (60 h) has been studied. The results indicate that the c...Influence of OH -/SiO 2 ratio (alkalinity) on the particle size distribution and structure of the β zeolite synthesized during a shorter crystallization period (60 h) has been studied. The results indicate that the characteristic point of crystallinity of synthetic zeolite is at alkalinity of 0 23～0 24. When the alkalinity is higher than 0 39, β zeolite can not be obtained. The difference of crystal size between the zeolites synthesized from gels with different alkalinity is 0 7～0 8 μm. Along with the increase of the alkalinity, the particle size distribution varies from narrow to wide and again from wide to narrow, and the framework Si/Al ratio by 29 Si NMR increases gradually and then decreases, but the change of OhAl/TdAl ratio by 27 Al NMR is contrary to that of framework Si/Al ratio. In addition, the Si(OH) site existing in the TEA β is confirmed by NMR.展开更多
文摘Influence of OH -/SiO 2 ratio (alkalinity) on the particle size distribution and structure of the β zeolite synthesized during a shorter crystallization period (60 h) has been studied. The results indicate that the characteristic point of crystallinity of synthetic zeolite is at alkalinity of 0 23～0 24. When the alkalinity is higher than 0 39, β zeolite can not be obtained. The difference of crystal size between the zeolites synthesized from gels with different alkalinity is 0 7～0 8 μm. Along with the increase of the alkalinity, the particle size distribution varies from narrow to wide and again from wide to narrow, and the framework Si/Al ratio by 29 Si NMR increases gradually and then decreases, but the change of OhAl/TdAl ratio by 27 Al NMR is contrary to that of framework Si/Al ratio. In addition, the Si(OH) site existing in the TEA β is confirmed by NMR.
